U.S. patent application number 15/026559 was filed with the patent office on 2016-08-25 for dental kit-of-parts and method of assembling the same.
The applicant listed for this patent is NOBEL BIOCARE SERVICES AG. Invention is credited to Nicolai Bernhard.
Application Number | 20160242877 15/026559 |
Document ID | / |
Family ID | 49585149 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160242877 |
Kind Code |
A1 |
Bernhard; Nicolai |
August 25, 2016 |
DENTAL KIT-OF-PARTS AND METHOD OF ASSEMBLING THE SAME
Abstract
The present invention describes a dental kit-of-parts comprising
an implant abutment, a dental restoration and a screw. The head of
the screw is provided in a recess formed in the kit-of-parts, with
the screw shaft extending through a hole in the implant abutment. A
channel in the dental restoration allows access to the screw head
by a tool, wherein the diameter of the channel is smaller than the
diameter of the screw head. The dental kit-of parts can be
manufactured using rapid prototyping such that the captive screw is
formed within the combination of the implant abutment and the
dental restoration or through conventional means, with the dental
abutment and the dental restoration being ex-situ connected to
enclose the screw.
Inventors: |
Bernhard; Nicolai;
(Winterthur, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOBEL BIOCARE SERVICES AG |
Kloten |
|
CH |
|
|
Family ID: |
49585149 |
Appl. No.: |
15/026559 |
Filed: |
September 25, 2014 |
PCT Filed: |
September 25, 2014 |
PCT NO: |
PCT/EP2014/070443 |
371 Date: |
March 31, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61C 13/0018 20130101;
A61C 13/0019 20130101; A61C 19/02 20130101; B33Y 80/00 20141201;
A61C 8/0016 20130101; A61C 8/005 20130101; A61C 8/0068 20130101;
A61C 13/0013 20130101; B33Y 10/00 20141201; A61C 8/0089
20130101 |
International
Class: |
A61C 8/00 20060101
A61C008/00; A61C 13/00 20060101 A61C013/00; A61C 19/02 20060101
A61C019/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2013 |
GB |
1317400.8 |
Claims
1. Dental kit-of-parts comprising: an implant abutment having an
inner surface and an outer surface, and a through hole configured
to accommodate at least part of a screw shaft herein, the implant
abutment being configured to be connected to a dental implant
implanted in a jawbone; a dental restoration having an inner
surface and an outer surface and a channel through which a tool is
insertable, the dental restoration being configured to be connected
with its inner surface to the inner surface of the implant
abutment; and a screw having a screw head and a threaded screw
shaft, the diameter of the screw head being larger than the
diameter of the screw shaft; the kit-of-parts being so configured
that the screw can connect a pre-assembly of the implant abutment
and the dental restoration to the dental implant; and the
pre-assembly being so configured as to comprise therein a recess
that encloses the screw head, whereby the screw is a captive screw;
in which kit-of-parts the channel of the dental restoration
connects the outer surface of the dental restoration to the recess
and has a diameter smaller than a diameter of the screw head of the
screw; and/or and in which kit-of-parts the recess is formed within
the dental restoration such that the recess is enclosed by the
dental restoration and has no open sides to a peripheral surface of
the dental restoration.
2. Dental kit-of-parts according to claim 1, wherein the recess is
positioned between the implant abutment and the dental
restoration.
3. Dental kit-of-parts according to claim 1, wherein the dental
restoration is connected to the outer surface of the dental
restoration via a through hole in the dental restoration configured
to accommodate at least part of the screw shaft therein and having
a diameter smaller than a diameter of the screw head and larger
than a diameter of the screw shaft.
4. Dental kit-of-parts according to claim 1, wherein the dental
restoration is configured to be splittable in at least two
parts.
5. Dental kit-of-parts according to claim 1, wherein a longitudinal
extension of the channel coincides with or is angled relative to a
longitudinal axis of the screw shaft.
6. Dental kit-of-parts according to claim 5, wherein an angulation
of the longitudinal extension of the channel relative to the
longitudinal axis of the screw shaft is 0.degree. to
30.degree..
7. Dental kit-of-parts according to claim 1, wherein the implant
abutment is provided with a protrusion and the dental restoration
with a receiving section, wherein in the pre-assembly, the
protrusion and the receiving section matingly engage each
other.
8. Dental kit-of-parts according to claim 1, wherein the dental
restoration comprises a crown, a bar, or a bridge structure.
9. Dental kit-of-parts according to claim 1, wherein at least one
of the parts of the dental kit-of-parts comprises at least one
material selected from the group of: polymers,
polymethylmethacrylate, polyurethane, polyether ether ketone;
reinforced polymers, reinforced by glass fibers, carbon fibers and
ceramic particles; dental hybrid ceramics; glass ceramics; titanium
and titanium alloys; cobalt chromium alloys; zirconia and
alumina.
10. Dental kit-of-parts according to claim 1, wherein at least one
of the parts of the dental kit-of-parts is formed by at least one
selected from the group of: rapid manufacturing, selective laser
melting, selective laser sintering, electron beam melting, direct
metal laser sintering, stereolithography, three-dimensional
printing and fused deposition modeling; casting, molding and
machining.
11. Dental kit-of-parts according to claim 1, wherein the
connection between the inner surface of the implant abutment and
the inner surface of the dental restoration is formed by at least
one selected from the group of: chemical bonding, gluing, bonding
and cementing; thermal bonding, laser welding, friction welding;
and mechanical bonding, press-fitting, shrink-fitting, screwing and
bolting.
12. Dental kit-of-parts according to claim 1, wherein the screw
comprises an amorphous metal material and an amorphous metal alloy,
wherein the amorphous metal material and the amorphous metal alloy
is a bulk metallic glass.
13. Dental kit-of-parts according to claim 12, wherein the screw
comprises the amorphous metal material or the amorphous metal alloy
in bulk.
14. Dental kit-of-parts according claim 1, comprising: a dental
implant configured to be implanted into a jawbone; and tooling
configured to adjust and fasten the dental implant, the implant
abutment and the dental restoration.
15. Dental kit-of-parts according to claim 14, wherein the tooling
comprises an amorphous metal material and an amorphous metal alloy,
wherein the amorphous metal material and the amorphous metal alloy
is a bulk metallic glass
16. Dental kit-of-parts according to claim 15, wherein the part of
the tooling which engages the screw comprises the amorphous metal
material or the amorphous metal alloy in bulk.
17. Dental kit-of-parts according to claim 1, comprising: a
plurality of said screws, individual ones of the plurality of
screws having different geometrical features for engagement of a
tool, and a plurality of said implant abutments, individual ones of
the implant abutments having different geometrical features capable
of preventing rotation between the individual abutment and a dental
implant.
18. Method of manufacturing a dental kit-of-parts, as claimed in
claim 1, comprising the following steps: aligning the implant
abutment and the dental restoration; positioning the screw between
the implant abutment and the dental restoration; assembling the
implant abutment and the dental restoration via the surface of the
implant abutment and the inner surface of the dental restoration,
with the screw head positioned in the recess and at least part of
the screw shaft accommodated in the through hole of the implant
abutment, thereby forming a pre-assembly of the implant abutment
and the dental restoration for subsequent assembly of the
pre-assembly with a dental implant and prior to the step of forming
the pre-assembly, the steps of: manufacturing the dental
restoration by means of rapid manufacturing such that the recess
and the through hole of the dental restoration are formed within
the dental restoration; and manufacturing of the screw
simultaneously with the previous step, such that the screw head is
formed in the recess and the screw shaft is formed in the through
hole of the dental restoration and the screw is a captive screw
enclosed by the dental restoration.
19. Method of manufacturing a dental kit-of-parts according to
claim 18, wherein the step of assembling the implant abutment and
the dental restoration further comprises: a step of fixedly
connecting the implant abutment and the dental restoration with the
screw head enclosed therein, wherein the step of fixedly connecting
the implant abutment and the dental restoration comprises at least
one step selected from the group of: chemical bonding, gluing,
bonding and cementing; thermal bonding, laser welding, friction
welding; and mechanical bonding, press-fitting, shrink-fitting,
screwing and bolting.
20. (canceled)
21. Method of manufacturing a dental kit-of-parts according to
claim 18 further comprising, prior to the step of forming a
pre-assembly, the steps of: manufacturing a dental restoration by
means of rapid manufacturing such that a recess and a through hole
of the dental restoration are formed within the dental restoration;
and pausing the method of rapid manufacturing at a stage where the
recess is partially formed; positioning the screw inside the dental
restoration such that the screw head is positioned in the partial
recess and the screw shaft is at least partially accommodated in
the through hole; continuing the rapid manufacturing process until
the inlayed screw is fully enclosed by the dental restoration and
the dental restoration is completed.
22. Method of manufacturing a dental kit-of-parts according to
claim 20, wherein the method of rapid manufacturing comprises at
least one selected from the group of: laser melting, selective
laser sintering, electron beam melting, direct metal laser
sintering, stereolithography, three-dimensional printing and fused
deposition modeling.
23. Method of manufacturing a dental kit-of-parts according to
claim 18, wherein at least the step of forming a pre-assembly is
performed ex-situ.
24. Method of manufacturing a dental kit-of-parts according to
claim 18, wherein the screw and the tooling are formed by net shape
casting.
Description
TECHNICAL FIELD
[0001] The present invention relates to a dental kit-of-parts for
use in dental restoration and a method of manufacturing said dental
kit-of-parts.
BACKGROUND ART
[0002] Multi-piece osseointegrated dental restorations may consist
of an dental implant (also referred to as fixture or implant
fixture) that is fixedly implanted into the jawbone, an implant
abutment (also referred to as adapter or spacer) that is connected
to the dental implant and mediates the connection between the
dental implant in the jawbone and a dental restoration (for example
a crown or bridge structure), which is the visible, tooth-shaped
prosthetics with the functional and aesthetic requirements of that
of natural teeth, sitting on top of the dental implant. The
combination of implant abutment and dental restoration may also be
referred to as dental superstructure, which can be connected to the
dental implant via a screw that engages with a thread in the dental
implant, thereby mechanically joining the implant and the dental
superstructure. The dental restoration is commonly joined to the
implant abutment by means of bonding agents like dental cement or
adhesives, or via a screw connection. For a more detailed insight
into osseointegrated implants, the reader is referred to the
standard work: "Osseointegrated implants" by P-I Branemark,
Scandinavian Journal of Plastic and Reconstructive Surgery,
Supplement No. 16, 1977, Almquist & Wiksell International (in
the following referred to as Reference 1).
[0003] In two-piece designs problems may arise from the use of
bonding agents in-situ (i.e. in a patient's mouth), where such
agents are normally employed in excess to ensure proper closing of
an inevitable gap that is formed when the two pieces are joined.
Such excess bonding agent may accidentally reach other parts of the
implant and could be hard to be removed from there. It can also
form inaccessible pockets and cause inflammation or failure of the
implant. In addition, in conventional in-situ assembly of dental
prosthesis, the screw to connect the dental superstructure to the
implant has to be handled separately in the mouth region. This
bears the risk of the normally fairly small sized screw getting
lost and the patient swallowing or even choking on it. Also,
handling a small screw can be bothersome and time consuming. A
partial remedy may be the use of one-piece implant as described in
WO 2008/138644, where an implant abutment is integrally formed with
a screw part, but this may reduce the flexibility of the prosthesis
and also limits the number of possible combinations of material
that can be used, since normally the one-piece implant is only made
of a single material.
[0004] Conventionally, the dental restoration is provided with a
channel through which the screw is inserted to reach the hole
connecting the implant abutment and the implant and also to insert
therethrough tools to fasten the screw during assembly. Since it is
required that a complete screw can be inserted through the channel,
said channels are often rather large compared to the overall size
of the dental restoration and thus constitute mechanical weaknesses
reducing its robustness and resilience. Furthermore, the channels
required equally large exit holes on the surface of the dental
restoration which are at least unaesthetic. Additionally, they are
also problematic on functional surfaces, for example, on occlusal
surfaces, which experience high loads and should thus not possess
discontinuities in the form of openings. Hence, the channels are
angled relative to a screw axis so that the channel exits on faces
of the dental restoration that are less visible and do not bear
high loads as described in WO 2008/024062 A2. However, this
approach implies that the exit holes are also more difficult to be
accessed by the dentist and often special tooling is required that
is configured to be inserted through such angulated channels as
described in WO 2007/078137 A1.
Problem to be Solved
[0005] The present invention seeks to provide a dental kit-of-parts
with increased flexibility and adaptability to the individual
pre-requisites and needs of a patient alongside with higher ease of
handling when the dental kit-of-parts is employed in dental
therapy. The above mentioned problems and drawbacks will be
addressed by the dental kit-of-parts accordingly.
[0006] The problem is solved by the dental kit-of-parts according
to claim 1. Further embodiments of the dental kit-of-parts
according to claim 1 are described in the respective dependent
claims 2 to 17. The problem is further solved by the method of
manufacturing a dental kit-of-parts according to claim 18.
Embodiments of the method according to claim 18 are described in
the respective dependent claims 19 to 24.
BRIEF DESCRIPTION OF FIGURES
[0007] The various aspects, features and advantages of the present
invention will become apparent from the following description of
embodiments and ways of carrying out the invention in combination
with the following accompanying drawings, in which:
[0008] FIG. 1 depicts a schematic, cross-sectional exploded view of
a dental kit-of-parts according to one embodiment and a dental
implant;
[0009] FIG. 2 is a schematic, cross-sectional view of an assembled
state of a dental kit-of-parts connected to a dental implant;
[0010] FIG. 3 depicts a schematic, cross-sectional exploded view of
a dental kit-of-parts according to another embodiment and a dental
implant;
[0011] FIGS. 4A and 4B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to a further embodiment and
of that dental kit-of-parts together with a dental implant,
respectively;
[0012] FIGS. 5A and 5B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to yet another embodiment
and of that dental kit-of-parts together with a dental implant,
respectively;
[0013] FIGS. 6A and 6B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to another embodiment and
of that dental kit-of-parts together with a dental implant,
respectively.
WAYS OF CARRYING OUT THE INVENTION
[0014] Specific embodiments and way of carrying out the invention
will now be described in detail with reference to the accompanying
drawings. The embodiments are not intended to unduly limit the
invention, but are rather provided so that the disclosure will be
thorough, complete and will fully convey the scope of the invention
to the skilled person. Terminology used in the description is not
intended to be limiting the invention either. Further, the drawings
are exemplary schematic drawings and not every figure necessarily
contains all of the features contained in preceding figures. This
is however not to be construed to be limiting or excluding and was
done only to highlight additional features and developments. Also,
in the drawings, like reference numerals refer to like
elements.
[0015] FIG. 1 depicts a schematic, cross-sectional exploded view of
a dental kit-of-parts according to one embodiment and a dental
implant.
[0016] The dental kit-of-parts comprises an implant abutment 2, a
dental restoration 4 and a screw 3.
[0017] In two-piece designs, the implant abutment 2 is an
intermediate, separate piece that mediates a connection between the
dental implant 1 fixedly connected to a jawbone and the dental
restoration 4. The implant abutment 2 is thus in physical contact
with the implant 1, i.e. in abutment with the dental implant 1, and
forms a solid foundation for the dental restoration 4. The implant
abutment 2 may consist itself of several sub-parts and various
designs are conceivable for the details of which it is referred to
Reference 1. The present invention is thus not limited to the mere
schematic design shown in the drawings. For instance, whilst the
drawings show a conical interface between the abutment and the
implant, the side walls of the interface need not taper.
Additionally, various forms of rotation prevention means can be
present, for instance as disclosed in WO 97/10769 A1 or WO
2006/012273 A1. The implant abutment 2 not only provides for a
robust and reliable basis for affixing the dental restoration 4, it
also confers flexibility and adaptability to the entire dental
prosthetics to account for the myriad of dental pre-requisites and
needs of each individual patient.
[0018] The dental restoration 4 is the aesthetic and functional
part of a complete dental prosthesis and connected to the dental
implant 1 via the implant abutment 2. As to be described later,
there are a number of ways of connecting the dental restoration 4
and the implant abutment 2. Both parts together form a dental
superstructure. From an aesthetic viewpoint, the dental restoration
4 should resemble a natural tooth as closely as possible, for
example, in color and shape. Basically, when visible, the dental
restoration 4 is supposed to be indistinguishable from a natural
tooth and should naturally blend in the denture. For labial teeth,
the dental restoration 4 should also mimic the incisal translucency
of the enamel. From a functional point of view, the dental
restoration 4 needs to possess sufficient mechanical strength and
durability to enable the patient to fully employ the dental
prosthesis for biting and chewing without discomfort or steric
limitations. Biting forces can be very high and the dental
restoration 4 is so designed as to withstand the loads encountered.
In its simplest form, the dental restoration 4 may be in the form
of a single tooth, but is however not limited thereto and may
further be an array of teeth forming a dental crown.
[0019] The screw 3 is a screw suitable for use in dental
applications and includes a screw head 9 and a threaded screw shaft
10. In this as well as in all other embodiments, the screw shaft 10
can be threaded over its full or over part of its length. The screw
3 is so designed that a diameter of the screw head 9 is larger than
a diameter of the screw shaft 10. In this as well as in all the
other depicted embodiments, the diameter is shown as the single
outside dimension of a cylindrical screw head in a direction
perpendicular to the axis of the shaft. In terms of the invention,
however, the term diameter is not to be understood as implying a
circular or cylindrical shape. Rather, the outer contour of the
screw head 9 when viewed in the direction of the axis of the shaft
can be round, polygonal or can have any other regular or irregular
shape. This equally applies to the cross-sectional shape of the
screw shaft in those parts where there is no thread. The diameter
is to be understood as the largest linear dimension across the body
of the head, or shaft, of the screw in a direction transverse to
the axis of the shaft. The screw head 3 is further configured so
that a tool can engage the screw head for performing a rotation of
the entire screw 3. The screw 3 is configured to connect a
pre-assembly that includes the implant abutment 2 and the dental
restoration 4 to an implant 1. The connection is established by the
screw shaft 10 being thread engaged with a corresponding thread of
a dental implant 1 fixed in the jawbone, whereby the pre-assembly
is fixedly positioned in the patient's mouth.
[0020] A schematic, cross-sectional view of an assembled state of a
dental kit-of-parts and an implant 1 as depicted in FIG. 1, is
shown in FIG. 2. The dental implant 1 is fixedly connected to a
jawbone. The implant abutment 2 is mated with, for instance
partially inserted into the dental implant 1, which is so
configured to provide a mating part that can accommodate the
implant abutment 2. The dental screw 3 is inserted through a
through hole 5 formed in the implant abutment 2 and a thread
engages with a corresponding part of the dental implant 1. By
fastening the screw 3, the screw head 9 abuts a screw seat, here
formed by the inner surface 6 of the implant abutment 2, and is
pushed towards dental implant 1 and fixedly connected thereto.
Furthermore, the dental restoration 4 is connected to the implant
abutment 2 via an interface 14 formed therebetween and that
interface intersects an outer surface of the pre-assembly. In other
words, an interface is formed where the two pieces merge and a
joint or seam exists that is exposed to the patient's mouth. The
outer surface is to be understood as the outer periphery of the
pre-assembly 15 with respect to the mouth, that is to say the
buccal and lingual as well as the interproximal and coronal sides.
The dental restoration 4 comprises a recess 12 configured to
accommodate the screw head 9 when the pre-assembly 15 is formed.
The dental restoration 4 also includes a channel 11 through which a
tool is insertable. The channel has a diameter that is smaller than
that of the screw head 9. The channel may further have a diameter
larger than that of the screw shaft 10, but that is not necessarily
the case. The channel is configured to connect an outer surface 8
of the dental restoration 4 to the recess 12. Here, the outer
surface 8 is to be understood as a boundary surface, a periphery,
between the patient's mouths and the bulk of the dental restoration
4. In this particular embodiment, both, a longitudinal extension of
the channel 11 and a longitudinal axis of the screw shaft 10
coincide with the axis L. The channel's 11 main extension is
therefore aligned with the longitudinal axis of the screw shaft 10.
Different alignments are also within the scope of this embodiment.
In a state where the dental restoration 4 is connected to the
implant abutment 2, the screw head 9 is enclosed in the recess, or
space, 12 positioned between the implant abutment 2 and the dental
restoration 4. In other words, the screw 9 is "trapped" between
these two pieces and becomes a captive screw that cannot be lost
from the pre-assembly 15. It is thus preferred that the recess 12
is formed between the two pieces. The term "recess" is not to be
understood as requiring any specific way of making it. It is simply
a room, space, or enclosure. Further, in that state, a tool can be
inserted through and along the channel 11, engage with the screw
head 9 and fasten the screw 3. In that state also, the connection
between the implant abutment 2 and the dental restoration 4 is
established via an inner surface 6 of the implant abutment 2 and an
inner surface 7 of the dental restoration 4. As inner surfaces,
surfaces are to be construed that are not normally exposed to the
patient's mouth, but enclosed by the pre-assembly 15, when the
pre-assembly 15 is formed. In other words, these surfaces are
internal surfaces of the pre-assembly 15 and as such literally
contrary to the outer surface 8.
[0021] The interface 14 between the implant abutment 2 and the
dental restoration 4 is formed by at least one from the group of,
but not limited to: chemical bonding, preferably gluing, bonding
and cementing; thermal bonding, preferably laser welding, friction
welding; and mechanical bonding, preferably press-fitting,
shrink-fitting, screwing and bolting. Accordingly, the interface 14
and mating surfaces of the implant abutment 2 and the dental
restoration 4 may comprise layers of dental adhesives or cements,
or layers that result from thermal modifications of the adjacent
material. In addition, the interface 14 may include mechanical
fixing means.
[0022] As regards the various parts of the dental kit-of-parts, the
parts may comprise a variety of materials from the group of, but
not limited to: polymers preferably polymethylmethacrylate,
polyurethane, polyether ether ketone; reinforced polymers,
preferably reinforced by glass fibers, carbon fibers and/or ceramic
particles; dental hybrid ceramics; glass ceramics; titanium and
titanium alloys; cobalt chromium alloys; zirconia and alumina. The
choice of material depends on the individual part of the kit and
further strongly on the needs and prerequisites of the patient and
has to made on a case-by-case basis. For example, for temporary
dental prosthetics, polymers and/or reinforced polymers are
preferred. For long-term prosthetics hybrid ceramics, glass
ceramics, the above metals and alloys or oxide ceramics like
zirconia and alumina are favored. For the screw 3, high performance
steel or even super high performance materials, for instance,
amorphous metals are preferred in order to keep the screw as small
as possible whilst retaining sufficient mechanical strength for
proper fixation. The choice of materials is thus independent of the
channel and interface designs as contemplated by the invention.
[0023] Similar to the bespoke choice of materials for the parts of
the dental kit-of-parts, a suitable way these parts were formed can
be selected from, but is not limited to the group of: additive
manufacturing, preferably, selective laser melting, selective laser
sintering, electron beam melting, direct metal laser sintering,
stereolithography, three-dimensional printing and fused deposition
modeling; molding, casting and machining.
[0024] A related method of manufacturing the above dental
kit-of-parts comprises forming the pre-assembly 15 by aligning the
implant abutment 2 and the dental restoration 4. Then the screw 3
is positioned between the implant abutment 2 and the two pieces are
assembled via the inner surface 6 of the implant abutment and the
inner surface 7 of the dental restoration 4, with the screw head 9
positioned in the recess 12 and at least part of the screw shaft 10
accommodated in the through hole 5 of the implant abutment. In that
step of forming the pre-assembly 15, the implant abutment 2 and the
dental restoration 4 are fixedly connected with the screw head 9
enclosed therein, wherein the implant abutment 2 and the dental
restoration 4 are connect by at least one method from the group of:
chemical bonding, preferably gluing, bonding and cementing; thermal
bonding, preferably laser welding, friction welding and mechanical
bonding, preferably press-fitting, shrink-fitting, screwing and
bolting. It is preferred that at least the step of forming the
pre-assembly is performed ex-situ, i.e., outside a patient's mouth.
There is also preferably no temporal relation required between
forming the pre-assembly 15 and the dental treatment. Hence, the
assembling can be carried-out completely independently to the
actual treatment of the patient.
[0025] The above dental kit-of-parts and the method of
manufacturing the same possess a number of significant advantages
over conventional kits and methods.
[0026] The channel 11 of the dental restoration 4 is significantly
narrower as compared to channels conventionally provided in dental
restorations. The latter were formed to not only insert tooling
therein, but also to insert the entire dental screw therethrough
for it to reach the implant abutment. It was consequently required
that the channel be sized so that a screw head can pass through.
Due to mechanical restrictions, the screw and screw head cannot be
downsized at will, since the screw is a load bearing component and
vital for the function and reliability of the prosthesis. Hence,
conventionally the channel was rather large compared to the overall
dimension of the dental restoration. The rather large discontinuity
caused by the channel in the dental restoration significantly
impeded its structural integrity and was a potential mechanical
weakness. Also, large channels implied rather large exit holes on
the surface of the dental restoration. These had aesthetical
drawbacks and thus were not formed in the parts of the restoration
to be placed in the mouth so that it becomes visible like, for
example, labial regions. Thus, such channels were normally required
to be angulated so that the exit hole emerged in in regions that
are less visible. However, this had as the result that they were
also inaccessible for the dentist, therefore requiring special
tooling and complicating the dental treatment. Besides the
aesthetical disadvantages, large exit holes also ought not to be
formed on functional surface of the tooth, for example occlusal
faces, due to the high loads there, which require a robust bulk
material. The above problems are mitigated by the present
invention. The screw 3 is placed inside a two-piece pre-assembly
15, which is then connected so that the screw 3 is enclosed
therein. There is thus no need to insert the entire screw through a
channel in the dental restoration. The channel 11 is downsized in
diameter to a size that suffices for a slim tool to be inserted.
Tools made of high strength materials have sufficient stiffness to
tighten the screw 3 whilst having a small diameter. Hence, the
diameter of the channel 11 can be reduced to an absolute minimum.
This means a much smaller exit hole 13 and an increased bulk
material cross-section of the dental restoration 4 going along with
increased mechanical strength. The much smaller exit hole 13
implies that it is no longer absolutely necessary to position these
hole away from visible or functional regions of the teeth, it may
in fact be placed again where it is most easily accessible to the
dentist. The channel may be angulated or curved, as in the prior
art, or straight and on axis, which the prior art sought to avoid,
or straight and off axis. The channel can have a cross section
which varies or does not vary with along the extension of the
channel.
[0027] In the dental kit-of-parts, the screw 9 is enclosed in the
pre-assembly 15 and becomes a captive screw. Conventional in-situ
assembling of two-piece prosthesis with loose screws bears the risk
of the normally fairly small sized screw getting lost and/or the
patient accidentally swallowing or even worse, chocking on it.
Also, handling a small screw can be bothersome and time consuming
for the dentist. These drawbacks are overcome by the present
invention where the dental screw is captively enclosed in a
pre-assembly 15. In the ex-situ method of manufacturing the dental
kit, it can be assembled well before the dental treatment and is
then transferred to the patient's mouth and connected to the dental
implant without the need of having to exercise extra care in
handling a small dental screw in-situ. This eases the treatment
significantly, reduces treatment time and risks and stress for the
patient.
[0028] Also, ex-situ assembly of a two-piece design dental
prosthesis means that various problems related to the use and
processing of bonding agents in-situ, for example, adhesives and
dental cements are avoided. The quality of the joint can much more
efficiently be achieved outside a patient's mouth and flexibility
is higher, since various other joining technologies can be applied
that are inapplicable in-situ. Also, the possible issues of having
to employ excess bonding agent to assuredly close a gap at the
interface between the pieces, which excess bonding agent may flow
out, be hard to remove and may even forms inaccessible pockets and
cause inflammation and failure of the entire implant, can be
avoided when assembling ex-situ as it is the case in the present
invention.
[0029] Further technical advantages related to ease of use: 1) no
mix-up of wrong screw in restoration: 2) enabling good handling as
not only screw picks-up, but now the whole restoration can be
picked-up with the embedded screw holding the abutment on the screw
driver.
[0030] FIG. 3 depicts a schematic, cross-sectional view of a dental
kit-of-parts according to another embodiment and a dental implant.
Explanations of features identical to those in the previous
embodiment will be omitted and only advanced or modified features
will be described here.
[0031] The dental kit-of-parts according to the present embodiment
also includes a dental restoration 4 with an angulated channel 11
whose longitudinal extension, here along a linear axis M, is tilted
with respect to the axis L coinciding with a longitudinal axis of
the screw shaft 10. This also implies that the exit hole 13 of the
channel emerges on a side surface of the dental restoration 4.
Preferably, the angle between L and M, i.e., the longitudinal
extension of the channel 11 and the axis of the screw shaft 10 is
between 0.degree. and 25.degree..
[0032] This embodiment can satisfy the need for providing a
flexible dental kit-of-claims that can be adapted to the patient's
individual prerequisites and needs that may at times demand the
provision of an angulated channel, for instance because its
placement in the mouth would otherwise not allow accessing the
channel with tools. Aesthetics can be improved and deleterious
effects of high chewing forces on the dental restoration 4, when
the exit hole 13 emerges, for example, on an occlusal surface, can
be further precluded.
[0033] FIGS. 4A and 4B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to a further embodiment and
of that dental kit-of-parts together with a dental implant,
respectively. Explanations of features identical to those in the
previous embodiments will be omitted and only advanced or modified
features will be described here.
[0034] As in the above described embodiments, this embodiment
comprises a recess 12 in the pre-assembly 15. It is formed between
the implant abutment 2 and the dental restoration 4.
[0035] Presently, the recess 12 is formed in the implant abutment 2
instead of the dental restoration 4. It thus ought to be evident
that the recess can be formed entirely in the abutment, entirely in
the restoration, or in both the abutment and the restoration. The
direction and course of the channel is independent of the formation
of the recess. In the present pre-assembly, the screw 9 is again
enclosed by the recess 12 in the implant abutment 2 and the
surrounding dental restoration 4, for example, its inner surface
7.
[0036] This embodiment confers the dental kit-of-parts additional
flexibility and adaptability. Depending on the material selection
and the methods employed, it may be preferred and easier to realize
the recess 12 in the implant abutment 2.
[0037] FIGS. 5A and 5B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to another embodiment and
of that dental kit-of-parts together with a dental implant,
respectively. Explanations of features identical to those in the
previous embodiments will be omitted and only advanced or modified
features will be described here.
[0038] This embodiment illustrates schematically an alternative way
of merging the implant abutment 2 and the dental restoration with
the help of assembling means. For instance, the implant abutment 2
is provided with a protrusion 16 and the dental restoration 4 with
a receiving section 17. In the pre-assembly 15, these two parts
matingly engage each other. In FIG. 5A a male-female configuration
is shown, in which the protrusion may have an annular shape and the
receiving section 17 so configured as to accommodate the protrusion
16 and to form a form fit, here a circular recess. The receiving
section 17 may be integrally formed as part of the recess 12.
However, possible configurations are not limited thereto. It is
also possible to reverse the male-female configuration, so that the
dental restoration 4 comprises a protrusion and the implant
abutment 2 the accordingly configured receiving section. In
addition, the protrusion 16 and/or the receiving section 17 may
comprise alignment and/or rotation prevention features (not shown)
so that the pre-assembling is restricted to distinct positions only
and degrees of freedom of movement in the mating process and once
mated are reduced so as to avoid misassembly or to improve
alignment accuracy of the individual pieces. Again, the direction
and course of the channel is independent of the other features
disclosed by this embodiment.
[0039] As said before, in the present embodiment, assembling
precision can be improved, since the assembly means restrict the
degrees of freedom during forming the pre-assembly 15. Also, time
spent on properly aligning the pieces of the dental kit-of-pats is
shortened, since the pieces "fall" in the right position almost
automatically. Moreover, the form fit increase the strength of the
connection between the implant abutment 2 and the dental
restoration 4 and may relieve the load bearing interface 14.
Consequently, it may also be possible to reduce amounts of bonding
agents to be used to connect the pieces of the pre-assembly 15.
[0040] FIGS. 6A and 6B depict a schematic, cross-sectional exploded
view of a dental kit-of-parts according to another embodiment and
of that dental kit-of-parts together with a dental implant,
respectively. Explanations of features identical to those in the
previous embodiments will be omitted and only advanced or modified
features will be described here.
[0041] In this embodiment, the recess 12 that encloses the screw
head 9 is formed within the dental restoration 4. This means the
recess 12 is enclosed by the dental restoration 4 and has no open
sides to a peripheral surface of the dental restoration 4, for
example, the inner surface 7. The recess 12 enclosed in the dental
restoration 4 is connected to the periphery of the dental
restoration 4 via a through hole 18 that is configured to
accommodate at least part of the screw shaft 10 therein and has a
diameter smaller than a diameter of the screw head 9 and larger
than the screw shaft 10. Hence, the screw shaft 10 is partly
exposed from the dental restoration 4, but the screw head 9 is
trapped therein, so that the screw 9 becomes a captive screw. The
face of the recess 12 that is intersected by the through hole 18
serves as a screw seat. In other words, in the present embodiment,
a space (recess 12) is formed inside the dental restoration 4, i.e.
in the bulk thereof. The screw is so accommodated in the bulk that
it is still functional. Functional means that the screw can be
operated and used as a connection/fixation means for the dental
kit-of-parts. At the same time, the screw is so accommodated in the
bulk that it cannot be unintentionally extracted therefrom without
destroying at least one of the dental restoration and the screw.
The shape, dimensions and design of that space are not particularly
limited, as long as the above functionality is ensured.
[0042] The dental kit-of-parts according to the present invention
preferably also comprises tooling (not shown) configured to adjust
and fasten the dental implant 1, the implant abutment 2 and the
dental restoration 4. The tooling is not limited to any particular
embodiment as long as it achieves the above functionality in dental
applications. One example is a simple screw driver to tighten screw
3 via engagement with the screw head 9. Further examples are the
Stargrip.TM. or the Unigrip.TM. screwdrivers from Nobel
Biocare.RTM.. More complex tooling is perceivable.
[0043] Another preferred embodiment, which is generally combinable
with most of the previously mentioned embodiments, is that the
screw 3 of the dental kit-of-parts comprises an amorphous metal
material and/or an amorphous metal alloy. It is further preferred
that said amorphous metal material and/or the amorphous metal alloy
is a bulk metallic glass. Moreover, it is preferred that this screw
consists of the amorphous metal material or the amorphous metal
alloy in bulk. The present preferred embodiment hence defines that
the screw 3 used as a connection/fixation means in the dental
kit-of-parts is at least partially, or optionally completely, made
of an amorphous metal material and/or an amorphous metal alloy,
preferably a bulk metallic glass. Non-limiting examples for said
materials are: the commercially available "Liquid Metal" and any
other biocompatible amorphous metal.
[0044] The screw thereby realizes the technical benefits and
advantages that go along with the properties of the amorphous metal
materials and alloys in dental applications and beyond, for
example, but not exclusively: 1) super high elasticity allowing
significant higher system pre-load; 2) high corrosion, wear and
scratch resistance; 3) a low MRI (Magnetic Resonance Imaging)
signature improving MRI-compatibility; 4) possibility of net-shape
forming as explained later. The superior mechanical properties
allow the transmission of high fastening/connecting forces at
reduced load bearing dimensions as compared to conventional metals.
By using amorphous metals for the dental screw, the minimal screw
dimensions conventionally assumed to be required to bear chewing
forces over a life-time and to resist chewing force peaks can be
circumvented. Specifically, this implies for the present embodiment
that the screw 3 can be generally downsized while maintaining its
intended function. Hence, the recess 12 could be reduced in size
thereby increasing the load bearing material cross-section, for
example, of the dental restoration 4 if formed therein. Also, the
holes 5 and 18 can be reduced in size as the screw shaft 10 is
reduced in size, which further contributes to the mechanical
integrity of the entities in which they are formed. In comparison
to conventional metals the friction of the screw is reduced which
enables a higher efficiency in converting screwing or tightening
torque, i.e. the torque used in fastening the screw, into holding
force. Put differently, for the same load bearing capacity as that
of a screw connection in conventional metal, a lower screwing
torque is required which, in turn, lowers the torque applied to the
implant when fastening the screw and achieves benefits in implant
stability.
[0045] Yet another preferred embodiment, which is also generally
combinable with most of the previously mentioned embodiments, is
that the tooling comprises an amorphous metal material and/or an
amorphous metal alloy. It if further preferred that the amorphous
metal material and/or the amorphous metal alloy is preferably a
bulk metallic glass. Moreover it is preferred that the tooling
consists of the amorphous metal material or the amorphous metal
alloy in bulk at least in those parts which engage the screw. This
delivers the load-bearing advantages also to the tooling so that
mechanical failure of the tooling upon fastening the screw is
avoided. The present preferred embodiment hence defines that the
tooling configured to adjust and fasten the dental implant, the
implant abutment and the dental restoration is at least partially
or optionally completely made of an amorphous metal material and/or
an amorphous metal alloy, preferably a bulk metallic glass.
Examples for said materials and technical benefits realized are at
least the ones previously mentioned. Specifically for the present
embodiment this implies that the tooling can be significantly
downsized, while still being fully functional to ensure proper
adjustment and fastening. At the same time, the channel 11 or any
opening in the dental kit-of-parts receiving said tooling can be
downsized in relation to the downsizing of the tooling. A reduced
diameter of the channel 11 increases the mechanical integrity of
the dental restoration 4. Furthermore, aesthetic impediments are
reduced, since the exit opening of the channel 11 is also reduced
in size and hence much less visible.
[0046] As indicated above, it is within the scope of this invention
that both the screw 3 and the tooling at the same time comprise or
consist of an amorphous metal material and/or an amorphous metal
alloy, preferably a bulk metallic glass. This combination then
results in a dental kit-of-parts, wherein all openings that either
receive the screw 3 and/or the tooling, for example 5, 11, 12 and
18, can be reduced in size, hence realizing a beneficial
combination of the above mentioned advantages. The minimization of
openings in the dental kit-of-parts also allows it to be downsized
altogether. Hence, it may, for example, be possible to produce and
apply dental restorations, which would, when using conventional
screws and tooling, not have enough load bearing material left to
be mechanically stable.
[0047] There are various possible ways of obtaining the above
dental kit-of-parts.
[0048] Firstly, the already described method of manufacturing a
dental kit-of-parts comprises before the step of forming a
pre-assembly additional steps. In this method, the dental
restoration 4 is manufactured by a method of additive manufacturing
such that the recess 12, the through hole 18 and the channel 12 of
the dental restoration 4 are formed within the dental restoration
4. And further, the screw 3 is manufactured simultaneously with the
previous step, preferably in-situ with the same production method.
This can, for instance be done in a rapid manufacturing machine.
The simultaneous manufacturing is performed such that the screw
head 9 is formed in the recess 12 and the screw shaft 10 is formed
in the though hole 18 of the dental restoration 4 and the screw 3
is a captive screw enclosed by the dental restoration 4. Methods of
rapid manufacturing allow for the manufacturing of parts with
complicated geometries, for example, with undercuts that are often
not at all obtainable by conventional molding and machining. Same
applies here. The present embodiment requires a complex
tooth-shaped part to be formed, wherein a recess, a through hole, a
channel and a screw are to be formed simultaneously with high
precision therein. Through the use of rapid manufacturing, the
assembly of the dental restoration 4 with enclosed screw 3 can be
"grown" layer-by-layer in a bottom-up approach. The resulting piece
is an exactly shaped dental restoration with a screw contained
therein. The growth process might require the growth of supporting
surfaces or ridges that hold the screw 9 during growth, but these
are designed as thin as possible so that the screw 9 can be broken
loose easily, for example, by inserting a suitable tool through the
channel 12 after the growth was completed. Alternatively, the screw
can also be chemically released by Aceton or other solvents.
[0049] Secondly, before the step of forming a pre-assembly, the
following alternative steps are conceivable. During the rapid
manufacturing growth of the dental restoration 4, the growth is
paused at a stage when the recess 12 is partially formed, for
instance for about 50%, and the screw 3 is positioned inside the
dental restoration 4 such that the screw head 9 is positioned in
the partially grown recess 12 and the screw shaft 10 is at least
partially accommodated in the through hole 18. After having inlayed
the screw 9, the rapid manufacturing process is continued until the
inlayed screw is fully enclosed by the dental restoration and
growth of the restoration is completed. In this alternative method,
the screw 3 is not necessarily grown simultaneously with the dental
restoration 4 or may even not be a part formed by rapid
manufacturing. For example, if a screw 3 of a super high strength
material, like amorphous metal, that cannot be grown simultaneously
via rapid manufacturing, is required, the screw 3 can nevertheless
be enclosed in the dental restoration 4 by interrupting the growth,
inserting the final screw 3 in the yet to be completed dental
restoration 4. The 50% growth is but one of several possible
examples for a state in which the screw can still be inserted in
the recess 12 and the through hole 18. Growth needs to be paused
before the recess 12 starts closing up, i.e. before the dental
restoration 4 starts enclosing the recess 12. Within this method
and the previous one, modifications are possible. The dental
restoration can be grown in an upright position, i.e. the growth
direction is substantially the direction of a longitudinal
direction of the dental restoration 4 (for example, along axis L in
FIG. 2) extending from a cervical base of the dental restoration 4
where the implant abutment 2 will be connected, towards the coronal
side of the dental restoration 4. Alternatively, growth can be
conducted in a lying position along a transvers axis that is
perpendicular to the longitudinal axis, i.e., extends from one of
the buccal, lingual, or interproximal surfaces towards an opposite
one of the dental restoration 4.
[0050] Thirdly, in case the dental restoration 4 is splittable,
parting planes maybe formed along the above longitudinal or
transversal direction so as to make the recess 12 and the trough
hole 18 accessible. A splittable dental restoration 4 maybe
achieved a priori by manufacturing two portions of the dental
restoration 4 by any suitable method of molding, casting, and/or
machining, or by employing rapid manufacturing or any other
suitable method to grow a dental restoration 4 with enclosed recess
12, through hole 18 and channel 11, which is then cut by any
suitable method along appropriate parting planes into at least two
portions so that a screw can be inserted. The portions of the
dental restoration may then be re-joined and fixedly connected by
any suitable method, preferably at least one from the group of:
chemical bonding, preferably gluing, bonding and cementing; thermal
bonding, preferably laser welding, friction welding and mechanical
bonding, preferably press-fitting, shrink-fitting, screwing and
bolting. After joining, the screw 3 is enclosed and thus becomes a
captive screw.
[0051] The mentioned methods of rapid manufacturing can preferably
be at least one from the group of: selective laser melting,
selective laser sintering, electron beam melting, direct metal
laser sintering, stereolithography, three-dimensional printing and
fused deposition modeling. For the alternative method where the
rapid manufacturing is paused, fused deposition modeling is more
preferably used, since the remaining dental restoration 4 can so be
best grown around the inlayed screw 3.
[0052] The above embodiment is advantageous in that the screw 3 is
enclosed in the dental restoration 4 and as such even further
secured against loss. During pre-assembly, handling is eased, since
the screw does need to be handled separately and only the dental
restoration 4 and the implant abutment 2 need to be merged. Also,
the dental restoration 4 and the implant abutment 2 are fixedly
connected by screw forces once the screw 3 engages with the dental
implant 1. When fastening the screw 3, the screw head 9 imparts a
force on the screw seat and pushes the dental restoration 4 and the
implant abutment 2 together so that the gap therebetween is closed.
This detachable force-fit connection require the use of bonding
agents like adhesives or cement and can thus avoid problems related
thereto. Advantages of single-piece designs are thus realized.
However, bonding agents may still be used to further secure the
connection between the two pieces, but the amounts required may be
reduced significantly.
[0053] In a further preferred method of manufacturing the dental
kit-of-parts, in particular, when the screw and/or tooling
comprises or consists of an amorphous metal and/or an amorphous
metal alloy, the screw and/or the tooling is formed by net shape
casting. It is a characteristic of amorphous metals that they do
not undergo a significant volume change at solidification.
As-casted products are hence close to final products and laborious
and expensive post-treatments, for example, finishing such as
machining or grinding can be avoided. The present invention
therefore provides a particularly efficient method for
manufacturing at least certain constituents of the dental
kit-of-parts.
[0054] Finally, another embodiment is the dental kit-of-parts
according to any one of the previously described embodiments also
includes a dental implant 1 that is configured to be implanted into
a jawbone and tooling that is configured to adjust and fasten the
dental implant 1, the implant abutment 2 and the dental restoration
4.
* * * * *